a man employed to count Rs.10710. He counts at the rate of of Rs.180 per minute for half an hour. After this he counts at the rate of Rs.3 less every minute than the preceding minute. find the time taken by him to count the entire amount

Asked by khushboo panwar | 15th Mar, 2011, 12:00: AM

Expert Answer:

Dear Student,
 
Here is the solution:
 

money counted in first 30 minutes=180x30=5400

money remained to be counted=10710-5400=5310

the further counting forms an AP,

first term=5310, second term=5307, 5304, ..........   0(last term)

where d=-3, first term=5310,an=0

an=a+(n-1)d

0=5310+(n-1)(-3)

solving for n, we get n=1771

total time taken for counting = 30 min+1771 min=1801 minutes

 

 

Hope this helps.
Regards
Team Topperlearning.

 

Answered by  | 16th Mar, 2011, 07:53: AM

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